Comparison of changes in soil heavy metal concentration under the influence of different water sources (Case study of Tehran 18th district)

The purpose of this study is the effect of two sources of well irrigation and surface runoff on soil heavy metal concentrations. Samples of well water, surface runoff and soil irrigated with well water and surface runoff were collected in District 18 of Tehran in different months. Concentrations of lead and cadmium in the samples were determined by atomic absorption spectrometry. The results of this study showed that in soil samples irrigated with surface runoff, the maximum concentrations of lead and cadmium were 52.5 and 0.64 mg/kg of dry soil, respectively, which is less than the allowable level of heavy elements in the soil. In well-irrigated soil samples, the maximum concentrations of lead and cadmium were 88 and 2.8 mg/kg of dry soil, respectively, which is more than the allowable limit and the reason can be due to the proximity of farms to the municipal sewage outlet. The average amount of lead and cadmium in well samples showed that it is very toxic for drinking and not for agricultural use. Samples of surface runoff water with lead content less than 0.05 and cadmium less than 0.03 mg / L Toxic for drinking and allowed for agriculture.